Homebrew PCBs

On Wed, 14 Sep 2005 03:14:29 +0200, Adam Seychell  
<a_seychell@...> wrote:

> Does anyone know if those flexible air bubble hoses used for fish tanks
> are any good for ferric or CuCl etch tanks ?
> see,  http://store1.yimg.com/I/animalworldnetwork_1863_24150004
> I know they have a lead metal insert that gives them ability to be
> shaped, and provides the weight. If this lead is not covered in plastic
> then it will not stand up to these etchants after a while. I've just
> ordered some to try, as I'm having bad luck with other "air stones" sold
> at aquarium stores.
> I've tried garden "soaker" hose, but the consistency of air release is
> very poor across its length. Its not designed for fish tanks.
> I've also tried a series of 1mm holes in PVC tube, but the air bubbles
> are too large causing very low back pressure. Again this gives very
> non-uniform bubbling across its length. I found the air volume needed to
> get good back pressure way too high (tested with water tank and a
> compressor).
> So I've come to conclusion you need lots of evenly distributed small
> bubbles to get uniform agitation.


I have one very identical to the one in the picture, only black.
I took the lead wire out, and then glued it to a plastic stick which i  
wedged into the tank with hot melt glue.
The bubbling holes are in two rows on one side on my hose, and i pointed  
them up.


It's still not entirely uniform, but it's OK now, and it would get even  
better with more pump power (have only 110 l/h on a 40cm hose).
The smaller the bubbles, the more there are, and more importantly the more  
they will travel sideways in a random manner before reacing the top (large  
ones are more buoyant and go up the same path each time).


Holds up well in CuCl.


ST